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creationism the flood

Uniformitarianism is dead! Long live catastrophism!

I had something pop up in my google alerts this morning, and it pointed to this article on creation.com. I don’t recommend clicking or reading unless you want a helping of brain hurt this early in the day. The part that was of interest to me reads:

By way of illustration, consider geologic formations in the Great Basin of the western United States. The vast horizontal layers of hydraulically deposited sedimentary rock are said to take long periods of time to accumulate, based on the assumption that the rate of deposition was always similar to that observed today in a typical river delta. This concept of uniformity may seem like a reasonable starting point when considered abstractly, but no steady-state river flow could possibly cover such a vast area; neither would it produce the violently buried and mangled bodies found fossilized in many rocks of the region. The present-day erosion conditions applied uniformly in the past could not account for the unusual formations of the Grand Canyon, mesas, badlands, and other canyons. By contrast, the catastrophic processes observed during and following the eruption of Mount St. Helens in the Cascades of Washington state produced a scale model of the Grand Canyon in a very brief period of time. Sediments were rapidly deposited and then suddenly eroded by pyroclastic steam, water, and mudflows in the area northwest of the summit. Now the canyon walls resemble others that are assumed to be of great age, even though they are known to be [merely decades] old.2

The point to be recognized is that science deals with observations of present states and processes, and can only discuss the prehistoric past. In the example of geologic formations of the Great Basin, the assumption of uniformity can be contrasted with a model of catastrophic tectonic, volcanic, and hydraulic activity that would accompany a global cataclysm such as the great Flood of Genesis. The observed eruption of Mount St. Helens demonstrated that rapid processes can produce effects commonly believed to require long periods of time, and thus gives credence, if not preference, to the concept that the earth’s geology did not require long periods of time to develop. Many puzzling formations can only be explained through cataclysmic forces. Similarly, other methods of estimating the age of the earth or of the universe apply assumptions about processes and rates that extend into the distant past. Regardless of how apparently compelling such dating methods may appear to be, the fact remains that they are built on assumptions that must be critically questioned and evaluated.

Wall of text crits you for 2K! (…sorry, little World of Warcraft joke there. You can slap me later.)

Basically, what he’s saying is:
– Strictly applying the observed depositional/erosional conditions of today to events of the past doesn’t explain everything perfectly.
– There’s evidence for catastrophism.
– Hey, there’s a canyon by Mt. St. Helens that’s like a scale model of the Grand Canyon and it formed in a matter of decades. Suck it, uniformitarians!

I’m not going to get in to the specific third claim here, because Talk Origins has already addressed it, and so very concisely. If someone actually stumbles upon this little bottled note in the vast oceans of the internet and would like me to get in to more detail than that, I definitely can.

What I really want to talk about are the first two points, because those are constantly belabored by creationists. There’s evidence for catastrophism! Incremental change doesn’t explain everything!

What this boils down to is a straw man, a disingenuous mischaracterization of uniformitarianism, and how geologists apply the principle.

So, what is Uniformitarianism, you ask? It’s the principle that as today, so in the past. It’s the assumption that the same laws of physics we’re operating under today are the same laws of physics there were over the billions of years of Earth history. It’s the principle that processes as we see and understand them today occurred in the same manner and to the same effect in the past.

What Uniformitarianism is NOT is the strict application of today’s processes to the past. It is not the assumption that if we cannot observe it in person, and in real time today, that it could not possibly have happened in the past.

If you were to apply Uniformitarianism in that manner, for example, you’d have no explanation for komatiite, which is an extrusive igneous rock from the Archean period. There are no rocks forming today that look like komatiite or have its same composition, because conditions on the Earth have changed over the last 2.5 billion years. In the Archean, the Earth was producing so much heat internally that it could produce a full melt of the mantle, and thus komatiite. Today, there’s only enough internal heat to allow for a partial melt, and thus we end up with basalt. So does that mean komatiite is impossible, because the Earth’s volcanoes aren’t spewing it forth today? No. And we understand why. Conditions have changed, following the same laws of physics and chemistry that we operate under today.

I’ve yet to meet a geologist who follows Uniformitarianism the way creationists like to envision it. Rather than assuming that nothing outside of the geologic processes of today could have possibly applied in the past, we instead use those processes to inform our understanding of the past. Creationists like to whine (yes, whine) that geologists refuse to accept that catastrophic events occur, because we’re uniformitarian sticks in the mud. This could not be further from the truth. Anyone that’s done even basic reading on volcanoes, earthquakes, glacial outburst floods, or landslides knows that catastrophic events can and do occur. We just don’t buy that your catastrophic event could occur because you’re incapable of explaining it without a flood (har har) of special pleading.

My favorite example of the reality of catastrophic geological events comes in the relationship between modern glacial outburst floods and the formation of the Channeled Scablands in Washington. (This was also my presentation topic for Skepticamp in Colorado this year.) The current scientific consensus about the Channeled Scablands is that they were formed by a massive, dare I say catastrophic, series of floods. The Cordilleran Ice Sheet formed an ice dam across the Clark Fork River, backing all that water up over a period of years to form Lake Missoula. (The old Lake Missoula bed is where present day Missoula, Montana is located. You can still see the old lake shore deposits in the hills.) When the lake became sufficiently big to partially float the ice dam (it was made of ice, after all) the dam failed catastrophically and the lake was able to drain in a matter of days. (If you’d like to read more about these giant floods, Discover the Ice Age Floods and Ice Age Floods Institute are a couple of good sites to start with.)

This theory of the Scablands formation is actually very new, and there was a lot of scientific pulling of hair and scratching at faces over it. This is obviously also not an event we have any chance of observing today, since it’s not the ice age, and the Cordilleran Ice Sheet is long gone. (Something for which the residents of western Washington State are no doubt grateful.) However, in modern times we can still observe glacial outburst floods of a much smaller variety, such as the floods from Hidden Creek Lake at the Kennicott Glacier. Research on these modern floods has certainly led to better understanding of how the ancient Lake Missoula/Cordilleran Ice Sheet floods worked.

Or look at it this way: Have we directly observed a Chicxulub-type impact event? I sure hope that we never will. But we’re still doing a lot of work on that and other impact sites, and we are using Uniformitarian principles, since the laws of physics that caused that meteor to hurtle into our planet are still most definitely in force.

So, Dr. Ashton, you are right. Strict adherence to uniformitarianism as you paint it explains very little of the past. And catastrophic events do occur. Strangely enough, geologists know and understand this concept well, and it’s created a robust body of evidence and theory to form our picture of the Earth’s 4.5 billion year geological history.

Unfortunately for you, we’re just a little too uniformitarian (the real sort) to buy the special pleading that the laws of physics have changed so that you can have your 6000 year old Earth.

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texas scares me

Just when we thought the Texas Board of Education couldn’t get any scarier.

For about five minutes, I had a little flutter of hope in my heart when Don McElroy was given the boot from the Texas Board of Education. He was an infamous creationist stooge, and every time I heard his name, I cringed. While I’m not Texan myself, I’m well aware of the influence that Texas has on the contents of school text books, and the worse science standards get in Texas, the more harm it does to children throughout the united states.

I should have known it wouldn’t last. Somehow the governor managed to dig up a candidate nearly as horrifying to head the board, Gail Lowe. She’s a prominent part of the conservative bloc on the board, and oh yeah, she’s a creationist. Quite an outspoken one, actually.

I weep. Considering that McElroy was trumpeted as an embarrassment to the state of Texas, I’m not sure how the governor thinks this will be an improvement. Though I suppose once he gets around to seceding from the union, we won’t be able to make fun of him any more.

This is all a prelude to the latest cringe-inducing education news coming out of Texas. They’ve set their sights on the teaching of history. Please go read, and then pick your jaw up off the floor and come back.

Seriously, are you kidding me? De-emphasize Thurgood Marshall, who led the charge in Brown v. Board of education, one of the most important Supreme Court decisions in the last century? Particularly when you consider that the argument for changing the standards seems to amount to this: “We’re in an all-out moral and spiritual civil war for the soul of America, and the record of American history is right at the heart of it.” (Rev. Peter Marshall)

That’s very, very scary. Thurgood Marshall, by helping desegregate schools, by chipping away at “separate but equal” throughout his career, is not a moral role model? His contributions deserve LESS emphasis? The man was a freaking SUPERHERO.

Considering the tired old argument about the Bible being the basis for the Constitution has been dragged out by this people, I think that says sad things about the education standards when they went through school. And since there’s further justification made by beating the dead horse of American exceptionalism, I suppose I shouldn’t be surprised. Coming soon: a return to the concept of manifest destiny!

You can make a lot of arguments regarding how scientific the study of history can truly be. I recently did a semester of British history at university, and it really opened my eyes to how skeptical – and just a bit scientific – you can be in regards to history education. That’s not something that you’ll find in K-12 any more. It involves giving the students historical sources, and helping them read and understand through the framework of what the world and people were like at that time. One of the best lessons in skepticism I ever had was reading The History of the Kings of Britain by Geoffrey of Monmouth and turning a skeptical eye on many of his more hilarious claims. (My personal favorite: At one point, the British invade Rome and sack it.*** No, really.)

I suppose that it’s too much to ask for US History to be taught like that in public school. But at the very least, could we refrain from directly misleading or lying to the kids if we’re not going to teach them how to understand history in a skeptical fashion?

History is written by the winners, indeed.

*** So, for example, this is how I’d start looking at his claim in a skeptical fashion:
– When did Monmouth write this? If it’s not a first hand account, how long after the fact is it?
– What are his sources? Are they reliable? Do they even exist?
– If this actually happened, what evidence should there be? If the Romans were too embarrassed to chronicle it, were there other countries around where the citizens would either not care and take note of it as good world gossip, or delight in the fact that Rome just got burnt to the ground?
– Are there any accounts written by British historians that repeat Monmouth’s claim that aren’t sourced either from him or directly from his source?
– What motive could Monmouth have if he were making up something this ridiculous? What was going on in Britain around the time he wrote this?

…and so on.

Categories
backyard geology

Backyard Geology: Garnet/Magnetite sands from the Great Lakes

One of my coworkers (a geologist that I do a lot of work for), who shall for the purposes of this blog be called “Tim,” recently went home to Michigan to visit his family. He brought back a very cool little sand sample that he’d scooped up off the beach at Lake Huron. On the site, the sand looked like very unremarkable brown sand, the kind you’d get off of any beach. Under the microscope, though, it had some real character!

When you look at sand through the lens of its characteristics as sediment, the three factors you’re most interested in are:

1) Sorting: If sand is “well sorted,” it means that most of the grains are about the same sign. The sorting of sediment has implications on how the sand was transported. For example, poorly sorted sediment might have come from something like a landslide, where everything got jumbled together, or from glacial till, which just gets pushed around indiscriminately by the glacier. Well sorted sediment indicates that there was probably longer transportation, and normally by wind or flowing water.

2) Size: Is it big or is it small? A lot (but definitely not all) of sediment begins its life as a larger rock, so this can also be an indication of length of transport, or mechanism that created the sediment.

3) Rounding: Is it round or is it angular? The more round a grain of sediment is, the more punishment its taken over the course of its life, which smooths out the rough edges. (A possible metaphor, here?)

The sand that Tim brought back from Lake Huron was pretty fine in size, very well sorted, and very well rounded. The sorting comes from the fact that it was put on a beach by the lake, and goes hand in hand with the particular grain size for that area of the beach. What the rounding means is that these sand grains have been worked a lot, no doubt by the lake, but possibly by other means.

The normal, average sand that those of us in the continental US are used to seeing is primarily made out of quartz. This is because quartz is very tough and very common as minerals go, so there’s lots of it, and it can take a lot of punishment without breaking down. What tells us the most interesting things about sand and where it came from are the other minerals that you can find in it.

In this case, there were very well rounded grains of deep red garnet, and also quite a bit of magnetite. This is some very cool stuff, and not what we see around in Colorado. Garnet comes pretty exclusively from metamorphic rocks, and magnetite is found in both igneous and metamorphic rocks. So the source of this sand was most likely metamorphic basement rock that’s been crunched up and worn down into sand.

Knowing what we do about the geologic history of the great lakes – they formed from the ice sheets melting at the end of the last ice age – this sand may very well have started its life as glacial till, dropped into the bottom of the newly formed lakes during the melting.

There was actually a very surprising amount of magnetite in the sample. Tim separated it out by dragging a magnet through the sand, and it made an impressive black fuzz. This is not necessarily how much magnetite you’d get if you dredged a similar sample from the bottom of the lake. Apparently streaks of black sand are common on the lake shorelines, because once the sand has had a chance to dry, the wind blows the lighter quartz and other mineral grains farther up the beach, leaving the heavy magnetite behind. So it’s very possible that the surprising amount of magnetite Tim brought home was due to this sorting action.

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A couple cool news stories.

Activity discovered at Yellowstone Supervolcano – I talked about supervolcanos a while back. Don’t worry, it’s still in no danger of blowing up any time soon. (And here, we’re talking geologically soon, which is a much, much longer span of time than a human soon.) The two cool things in this article are the discovery that the Tetons are getting shorter, and that there’s a “bulge” that’s expanded and deflated at Yellowstone.

The Tetons getting short is interesting because, in the normal course of things, mountains do get shorter. That’s just the way things work. Mountains are built, erosion wears them down. However, the Tetons are getting shorter much, much faster than they ought to be. Now why is that? Mountain ranges are normally criss-crossed with faults, some of which may be very, very large. The faults are from where the rock broke, unable to handle the strain, when the mountain range was thrust up. There’s a very large, active fault at the feet of the Tetons. The way such faults normally work when active is that the valley at the foot of the mountains drops, while the mountains move higher up. Except that the fault between the Tetons and their valley is going in the exact opposite direction as normal – the valley is rising, the mountains are sinking. It’ll be interesting to find out what the exact mechanism is. The current hypothesis is that this abnormal movement is due to the expansion and contraction of the Yellowstone volcano; the volcano puffs up, it pushes on the valley. The valley creeps up the side of the mountains, which forces them down.

Now, the “bulge” is actually a pretty normal thing, volcano-wise. Contrary to what you might think, rock is actually very elastic. If put under pressure (pressure that isn’t overwhelming, that is) for a long period of time, rocks will deform. When rocks are put under too much pressure too fast, they will break, which is what causes faults. Volcanoes tend to bulge as magma builds up, putting pressure on them from the inside. (One of the heralds of the Mt. Saint Helens eruption was the enormous bulge on the side of the mountain.) In many volcanoes, this bulge builds up and builds up until the volcano erupts. In this case, the bulge deflated a bit before rising again, which indicates a temporary relief of pressure; it also happened pretty rapidly – at seven inches in three years, that thing is sprinting when you think about things geologically. The bulge is probably caused by the movement of magma from the mantel plume that feeds Yellowstone.

* * *

Massive gypsum crystals in a cave in Mexico
These are SO COOL. Look at the first picture carefully – that’s a person in there for scale. These crystals are in a limestone cave, which was probably created by water from a hydrothermal vent coming in through a fault and dissolving the rock. (Limestone is very prone to dissolve when in contact with water.) The water deposited the minerals that formed these crystals (and the precious metal veins exploited in a nearby mine) and the crystals formed over time. The area is still very active as a hydrothermal vent; the temperature of the cave is around 125-150F and the air’s at a constant 100% humidity. Brutal!

If you didn’t know, hydrothermal activity is associated with volcanic activity. When rock is subducted at a plate boundary, it normally carries a lot of water with it. The water is superheated and seperates from the rock; it escapes rapidly through whatever avenues are available to it, normally through faults that form vents. Due to the nature of how the rock melts, the superheated water often carries rare elements with it (such as precious metals) that it deposits along the vents as it cools, moving to the surface.

The giant crystals in this picture are gypsum. Gypsum is a pretty cool mineral. It’s a 2 on Moh’s hardness scale, which means that you can scratch it with your fingernail. When you get a nice crystal that hasn’t been banged up (and it’s hard to find those, sometimes, because just about anything will mark gypsum because it’s so soft) they’re usually transparent. When you touch gypsum, it’s smooth and feels faintly soapy or waxy.

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Arkose & Alluvial Fans

Today was my second field trip with my Sed Strat class. We went up to Settlers’ Park to look at some exposed facies there. (A Facies is a group of sedimentary structures you see in a rock that points to a particular environment that the sediment was deposited in.) If you’re ever in the Boulder area and up for a little bit of an uphill hike, I recommend it. The facies we looked at belonged to the Fountain Formation and the Lyons Formation.

The Fountain Formation is pretty famous, at least locally. A formation is a unit of rock that is geographically contiguous (it’s all connected) and clearly seperate from the formations above and below. Sometimes this seperation is due to a change in rock type, since formations are usually of a single lithology – which is to say composed of just one type of rock. However, sometimes formations are seperated by unconformities, which are boundaries caused by erosion and other events.

So calling it the Fountain Formation means that it’s a big unit of a single kind of rock that covers a definite geographical area. (In this case, a broad swath at the feet of the east face of the Rocky Mountains.) Fountain is the name of the formation. It is composed of sandstones and Arkose; the Arkose is the most famous and gives it its beautiful color. Arkose is a particular kind of sedimentary rock. Arkose is normally primarily quartz, but it has at least 25% Feldspar in it. This will give the rock a definite pink cast, or if its been exposed to any weathering, the Feldspar will cause iron oxide (remember: rust is iron oxide) that stains the rock anywhere from orange to a beautiful, deep red.

A large portion of the Fountain Arkose was deposited by alluvial fans. Alluvial fans are a phenomena found at the base of mountains. What happens is that there are canyons through the mountains – formed by rivers. During the spring melt (or intense storms), massive amounts of water will flood through these canyons, picking up lots and lots of sediment along the way. These canyons let out at the base of the mountains, and the water suddenly spills out in a characteristic fan-shape. (To visualize this, turn on a hose that’s laying on the ground. Notice how the water spreads out in a fan at the end of the hose.)

While the water is shooting through the canyon, it’s going very, very fast. This translates to the water having a lot of energy – and the more energy water has, the bigger rocks it can carry. As the water spills out of the canyon, it loses a lot of that velocity because it’s no longer directed in a channel formed by the canyon walls. So it drops everything that it was carrying.

Alluvial fan deposits are very interesting to look at. They’re composed of layer after layer of different kinds of mudstones, sandstones, and conglomerates. When the water first comes out of the canyon, it drops all of the big rocks that it picked up – anything from coarse sand to even boulders! The rocks formed from that are conflomerates – there’s a wide range of how big the clasts (the bits of rock that the river dropped) are, and some of them are very large. At other times, the water wasn’t moving fast enough to carry large rocks, and it will just drop sand, or even mud. So you will layers with all different clast sizes in them. Mudstones are often far darker than the layers above and below them, so you will see stripes running through the formation.

The Fountain Arkose formed from the erosion of the Ancestral Rocky Mountains – the mounains that existed in the past before today’s Rockies. They were worn completely down, and then a new session of mountain building brought today’s Rockies up. The Ancestral Rockies were made of granite as well – that’s where the Feldspar in the Arkose comes from. Feldspar is an “unstable” mineral. It is subject to chemical weathering, and because of its physical properties, it breaks into tiny pieces easily. So large deposits of Feldspar are normally found close to their source. If they’re buried quickly, they can’t be weathered away!

If you want to see the Fountain Formation, there are many good places to see it in Colorado. In Boulder, you can go to Settlers’ Park, where its been uplifted into a hogback – the originally flat layers of rock are standing vertically. Also in Boulder, the Flatirons are part of that formation. Red Rocks Amphitheatre is built in another exposure of the Fountain Formation. It can also be seen in Garden of the Gods. If you ever have a chance to go to any of these places, I recommend it. They’re beautiful, and there’s some good hikes in those areas along with great geology!

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Why you should love sedimentary rocks.

New year, new semester, new tax return, new FAFSA. Where does the time go?

Mineralogy last semester ended well, though I can’t say I’m sorry to see it done. It takes a special kind of person to want to spend all your time staring into a petrographic microscope and thinking about 3-D crystalline forms. I got an A, and I wrote a rather boring paper about Enstatite, an igneous mineral that comes in rather pretty olive colored crystals. (Maybe I should post that paper here so you can look at it and… marvel, if that’s the word I want.)

This semester, my geology course is sedimentary stratigraphy.

Sedimentary rocks are pretty much the unsung heroes of the modern age. Well, to be precise, rocks in general are unsung heroes. They just sort of lay there, as far as most people are concerned, and they don’t actually do anything…

Except that they do. Off the top of my head, here’s what rocks have done for you lately:
1) Kept you from plummeting into an ocean of subsurface magma.
2) Supported your house, roads, office building, etc.
3) Provided some pretty scenary, if you live near mountains.
4) Acted as building materials (or storage for building materials) for at least half the objects you interact with on a daily basis.
5) And so on and so on.

But among the rocks, sedimentary rocks are the work horses for human concern. Now, all rocks are linked together, by something called the rock cycle. Sedimentary rocks are formed by the weathering and erosion of igenous, metamorphic, and even other sedimentary rocks. Weathering is the process by which rock is broken down into little pieces, and erosion is how those little pieces are carried away, most commonly by water, followed by wind and gravity. These little rock pieces are called clasts; they’re carried along by the wind or water and eventually dropped somewhere. This is called deposition. When enough clasts have been dropped in the same location, they build up, compact under their own weight, get covered with more clasts, and eventually get squished and cemented into a sedimentary rock.

That’s the really simple, basic view of it.

Unlike igenous or metamorphic rocks, sedimentary rocks don’t have to be melted or cooked or squished and twisted out of all recognizeable shape. This means that you find an absolute multitude of things in sedimentary rocks that you can’t possibly find in metamorphic or igneous rocks. Things like: Fossils (bones and footprints and things like that), oil, and drinking water.

Sedimentary rocks often also preserve ingenious little clues that tell us a great deal about where they were formed and what the Earth was like at that time, and in that place. You can find ripples preserved in rocks, mud cracks, even the impression of rain drops falling on a desert plain in the distant past. These rocks are our window into a time so far back that human beings didn’t exist to write down what was happening. Remember, in the lifetime of the earth, we are barely the blink of an eye.

So, every time you go to the museum and look at the dinosaur bones, you’re looking at something that was preserved in a sedimentary rock. Every time you put gas in your car, you’re using a product made from oil, which forms in shale (a sedimentary rock formed in deep water conditions), and then hides in subsurface reservoirs, most of them found in either sandstone or limestone (also sedimentary rocks). If you drink water from an aquifer, that water often has filtered a long distance through a formation of sandstone, which has acted as a natural filter so it’s clean to drink.

Isn’t that a weird though, water or oil flowing through rocks? In some of these reservoirs, it’s just finding its way through cracks in the rock. But in the case of sandstone, it is literally travelling through the rock. This is because of the way sandstone is made.

Sandstone is made of sand-sized clasts. Now, these clasts can really be any sort of rock or mineral, but most commonly you’ll find them made of quartz. This is because quartz is pretty hard, and has a property called conchoidal fracture. That means that when a little piece of quartz gets rolled or bumped along by the wind or water, it breaks in a special way. It doesn’t get sharp corners – it breaks in a very round, smooth fashion. So quartz sand, once its old enough and has been moved around enough, tends to be the roundest, smoothest sand you’ll ever find. Then when you pack this quartz sand together, there’s space between the little sand grains. Think about what it looks like when you put a bunch of marbles in a bowl. There’s still plenty of space in between the marbles for liquid to fit in, even if they’re packed as tightly as possible.

So, when you get a whole load of these quartz sand grains together and pack them in tightly, then squish them some more and cement them together to make a piece of sandstone, even if the rock looks solid, there’s actually a lot of empty space in it, hiding between the quartz grains!

This space is what oil and water move through. So when someone drills a well down to contact the sandstone the oil or water is in, it happily moves into the well – because the pressue in a well that goes all the way to the surface is a lot less than the pressure all that oil or water is under when it’s in a rock, under the ground.

There’s a lot more to talk about with sedimentary rocks. Hopefully I’ll be able to ramble about them some more, soon!

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Liquid Water on Mars

NASA has just released a statement saying that they’ve got good evidence of liquid water making an appearence on Mars some time in the last seven years.

BBC News Story

This is very exciting for several reasons. There is water on Mars that we know of, but it’s all locked in ice. (As an aside, did you realize that ice is a mineral? It’s the lowest density mineral that occurs on Earth.) But the most likely cause of this new gully that you can see in the photograph is liquid water! Liquid water is important because it’s necessary for life as we know it (so it once again introduces the possibility that we may some day find some sort of single-celled life on the red planet) and it’s also very important if we ever want to consider the possibility of building some sort of base or research station on Mars. We need a lot of water to survive, and it would make getting there and setting up shop a lot easier if we didn’t have to haul all of the water necessary with us.

Now, there has been evidence suggesting liquid water, though all of that was for much less recent events. A lot of the erosional forms on the surface of the planet point toward liquid water, though it could also be argued that the erosion could be caused by wind as well. (If you’re not actually there to look at things, it can be very difficult to tell the difference between erosion caused by liquid, wind, and simple wasting of loose material.) And there still is a possibility that this new gully was caused by mass wasting or even liquid carbon dioxide.

But liquid water is currently the best explanation.

This is all very exciting stuff!

High resolution images from the Mars Global Surveyor.

Phil Plait comments.

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HiRISE is made of win.

Finals are about to eat my brain. I had no idea school was just so exhausting.

But this cheers my day – and hopefully will cheer yours too!

HiRISE

High resolution images of the surface of Mars, some in color, some in grayscale. The files are enormous, and worth it. You end up with a single pixel being about a meter on the ground – which is AMAZING, considering that we’re talking about Mars, here. Some of topography is just stunning.

Being able to look at geological structures on the surface of Earth is cool enough. But we can really start comparing to what we’re seeing on Mars. It’ll give us some ideas of how certain features on the Martian surface formed, which will answer a lot of questions. (Though there’s a big one we’ll probably need to get in closer to answer – was the agent of erosion water or wind?)

Seeing all of this information streaming in from Mars gives me a lot of hope. My dream is that some day we’ll be able to send up some seismic instrument packages, though that will take a lot of doing. But think about it – being able to take a look at the subterranian geologic structure, and what that could tell us about the history of the planet. (And that would just be scratching the surface!) Some day, I hope… some day.

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70 million year old soft tissue.

Remember: scientists love it when the impossible happens. (At least when the impossible happens in an observable, empirical fashion.) It’s time for us to rethink our understanding of the process of fossilization. As we understand it now, this would have been impossible – but it happened! So now we need to work out the how and why. This is so COOL!

And here it is – soft tissue found with a 70 million year old fossilized dinosaur bone! A T-rex bone, to be precise. This is beyond cool. It means that they can do some biological comparisons between the Big T and birds, and they may even be able to sequence its DNA. Don’t worry, there’s a BIG difference between knowing an animal’s DNA and being able to clone it, so we won’t be seeing Jurassic (or in this case Cretaceous) park any time soon.

Scientists recover T-Rex soft tissue.

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What the space shuttle has done for you lately.

Yep, the space shuttle. And yet, it must be geology related – I’m writing about it, aren’t I?

There’s a nifty piece over at the Planetary Society blog about the Shuttle Radar Topography Mission. Basically, they got near-global topographical maps of the Earth out of this – more detailed than ever before!

Topography is very important to geology. It helps you figure out what’s lurking beneath the surface, and what forces might have acted to create the surface in the first place!

There’s a bunch of nifty links at the bottom of the article, which point to several specific pages of what they’ve figured out with the data. I suggest looking at the one about the rift valley in Tanzania and Mount St. Helens, since both are near and dear to my heart. But all of the information is way cool. (And some, like the information about New Orleans and its flood, is way important too.)